N251 exam 4: lecture 3 and 4

fairy ring

The circle of mushrooms that forms because the hyphae grow at an equal rate.
-seed is in center
-as it gets older circle will get wider

-fairies and devils
-before you enter a fairy ring, dance around it nine times
-if you enter, you may dance until you go mad or die of exhaustion
-time is said to move differently

fungi

-eukaryotes
-heterotrophs: plants are autotrophs, fungi need energy from other sources: either saprophytes or parasites
-cell wall made of chitin: plants have cellulose- gives structure
-lack chloroplasts: plants have
-mutinucleated cells: plants have one

general characteristics

-devoid of leaves, stems, or roots
-lack chlorophyll
-require an external carbon source (heteroptrophic)- saprophites or parasites
-carbon derived as saprophytes by adhering to decomposing nonliving organic matter
-carbon derived as parasites by invading living plants and animals

eukaryotic
-possess nucleus, nuclear membrane, endoplasmic reticulum, golgi apparatus, and mitochondria
-rigid cell wall composted of chitin: can absorb several dyes for identification

Saprophyte

An organism that feeds on dead matter

eukaryote

-no chloroplast in fungal cell
-bud scar on fungal cells; helps set a part from plant cells

plant cells: typically straighter sides
fungal cells: tend to have roundish or oval shape

General Characteristics

Yeasts
-single cells fungal form

molds
-multiple cells forming filamentous mycelium

spores
-fungi reproduce spores: sexual or assexual
-morphology, arrangement, and mode of derivation of spores serve as criteria for genus and species identification

molds

1. start with a spore
2. form germ tube
3. hypha
4. mycelium forms more complex part

bread mold
-usually when see it have a massive mycelium

general characteristics of fungi

Habitat
-found in nearly every habitat on earth where organic material exist
-light and small and travel through the air

Cordyceps fungus

spores infiltrate ants bodies and minds
-infects the brain
-the codyceps will erupt from the ants head-can take three weeks to grow and when finished deadly spores will burst from its tip then any ant in vicinity will be in risk of death
-can wipe out colonies of ants

a bunch of types that will specialize on one species of insects

the attacks stop from getting too many species of one kind

diseases caused by fungi

1. allergic reaction
-exposure causes person to become sensitized (immediate hypersentivites)
-if you have a mold allergy, your immune system overreacts when you breathe in mold spores. A mold allergy can cause coughing, itchy eyes and other symptoms
-in some people, mold allergy is linked to asthma and exposure causes restricted breathing and other airway symptoms
-spores are culprit

2. reaction to toxin
-hallucinogenic properties of some mushrooms
-poisonous effects of ergot fungus (rye smut)
-carcinogenic toxins of Aspergillus (aflatoxins)

3. Fungi that destroy human food supply
-wheat rust: Puccinia graminis
-Potato blight: Phytophthora infestans- happened in Ireland during victorian age- potatoes are clones- not many types were being grown and caused potato famine

4. Colonization of the human body by fungi (mycoses)
-superficial mycoses: on surface
-intermediate mycoses: specific tissue not yet disseminated
-systemic mycoses: entire body

ergot fungi

ergotism
-can grow on wheat and rye
-rye is more dangerous

ergotism

severe pathological syndrome affecting humans or other animals that have ingested plant material containing ergot alkaloid

causes:
-vasoconstriction leading to gangrene due to loss of blood circulation
-hallucinations
-irrational behavior
-convulsions
-death

Ergometrine

used to induce uterine contractions and to control bleeding after childbirth

aspergillus

can produce some toxins, cause allergic reactions, impact food supplies

-can be a representative of all four disease caused by fungi
ex: on CORN


aspergilliosis
-usual impacts people with impacted immune system
-fungus ball in lungs that may cause no symptoms and may be discovered only with chest x ray
-or have repeated coughing up of blood and chest pain
-can also get into blood stream
-can come and go at times

how do fungi infect

1. nasosinsues
-breathe in spores and get into lungs that way and spread
2. scratch/cut/catheters: get into blood
3. feed on fungal spores
4. skin: can land and start to grow

deep mycoses

treated systemically

subcutaneous and systemic fungus infections

1. Nocardiosis: lungs, lower extremeties

2. blastomycosis: inflammatory lesions in skin, lungs, or bones
-blastomyces dermatitis

3. coccidiomycosis
-respiratory disease

4. histoplasmosis: fungus infection of lungs with fever, anemia, loss of weight

5. cryptococcosis: systemic fungus infection of lungs or meninges

mycoses

1. superficial mycoses
-candidiasis-vaginal, thrush
-dermatophytes-athletes foot
-sporotrichosis- gardeners hazard
-blastomycosis- skin

2. intermediate mycoses
-aspergillus: lungs, gut ingested spores, fungal ball
-candidiasis: children and immunocompromised
-cryptococcus: pulmonary, cerebral
-all dimorphics: any organ
-mucomycosis: rhino cerebreal (nasal passeages and brain) pulmonary, gi, fungal ball

3. systemic mycoses
-mucormycosis: necrotizing, rapid, fulminating
-aspergillosis
-candidiasis
-cryptococcus
-all dimorphics

Candidiasis

thrush
-mouth

vaginal

SINGLE CELLULAR
-whitish growth

athletes foot

tinea pedis
-common skin infection of the webs of toes and soles of feet
-may spread to palms, groin and body
-itching, scaling, redness
-severe cases blister

Sporotrichosis

rose gardener's disease
-fungi gets through barrier of skin

Blastomycosis

large fungal growths
-large bumps

Dimorphics

Mycotic organisms that possess different morphological forms under different temperature conditions
-histoplasmosis
-blastomycosis
-coccidiomycosis

when in soil:
-at a cooler temp
-produce more spores
-in warmer situation, will grow through capsulated yeast stage (like when growing in human body)

Histoplasmosis

little dot like areas in xrays that show fungus

Mucormycosis

serious but rare fungal infections
-usually breathed in nose and invade and destroy massive areas on body
-typically associated with nasal passages
-can get into brain
-usually impacts someone with weakened immune system

crytococcus

can get into brain or meninges
-usually effect people with weakened immune systems

the good guys

Fungi as useful tools for genetic and biochemical studies
-neurospora crass (common mold) has been used for the above

yeasts have been genetically engineered to produce
-human insulin
-growth hormone
-somatostatin
-vaccine against viral hepatitis

Fungi as food
-mushrooms
-yeast in alcoholic beverages, breads

Fungi in symbiosis
-lichens: blue green crust on tree: algae gives fungus food production and the fungus will give the algae protection and structure
-often food source, benefits nature
-reindeer moss

laboratory diagnosis of fungal infections

Direct
-skin scrapings, hair, and nail clippings
-tissue imprints or sections: special stains

Culture
-handling of specimens in preparation for culture
-media

non selective
-sabourauds dextrose

selective:
-mycobiotic: antibiotics geared towards fungi
-sabouraud's with antibiotics (PCN, streptomycin, gentamicin, chloramphenicol)
-cyclohexamide: prevents overgrowth by mold contaminant

enriched
-brain heart infusion with blood
-potato dextrose agr: sporulation

identification

Prelimniary isolate observations
-yeast like (creamy, pasty, to mucoid)
-mold (cottony to wooly)
-rate of growth: molds grow quickly, yeast may take weeks
-colonies pigmentation: a lot of molds are
-growth on media containing anti-fungal agents
-dimorphic growth: at different temps
-co

mount preparations (molds)

Tease mount
-lactophenol aniline blue: common stain for both methods
-take needles or probes and take two to use to pull the mold a part
-want a thin layer of fungus, put on slide, and add stain and look under scope
-LOOK FOR SPORES OR CONIDIA (WHAT HOLDS SPORES)- looks different for different species of fungi

Scotch tape mount
-lactophenol aniline blue:
-touch sticky part of tape to fungus or mold to pick up then layer, add stain , then cover it with the tape to get a nice layer of mold

cool temp

mold

high temp

yeast

identification

can be done by:
-subculture
-biochemical tests
-DNA techniques to aid in identification

subculture

Yeast identification
-germ tube: candida albicans, gets done often
-corn meal agar preps looking for: good for growing
-get under scope and get various growth patterns

biochemical

Yeast identification

manufactured yeast identification kits
-API 20C: good for yeast ID

little plastic wells with dehydrated media, do a dilution of a pure culture of yeast-will inoculate wells with culture and let them incubate, then read biochemical reactions

DNA

serological diagnosis of fungal disease
-latex agglutination (candida): have latex particles that are coated in antibodies, mix with sample of unknown fungus, fungus has a specific antigen that antibodies will attach to, if positive= clumps of latex will appear, negative= even read
-similar to coagulase test in lab


-cryptococcal antigen assay (species-specific monoclonal antibodies):
using species specifical monoclonal antibodies and works like pregnancy test

-enzyme immunoassay (EIA):
antigen will bind to surface then antibody enzyme conjugate will attatch to antigen and cause a color change in the test

morels

best fungus of them all
-teachers fav mushroom to eat