Week 1 Flashcards
FUNGI
o Widely distributed in nature
o Natural habitats: (3)
o______ existence
water, soil, and decaying organic debris
Heterotrophic
Heterotrophic Existence
Unlike plants, fungi cannot produce their own food because they lack______. Instead, they absorb nutrients from external sources. Depending on how they obtain their nutrients, fungi can be classified as:
• ________– Decomposers that break down dead organic matter, recycling nutrients back into the ecosystem.
• ________– Fungi that form mutualistic relationships with other organisms (e.g., mycorrhizal fungi and plant roots).
• ________– Fungi that live on or within a host without causing harm (e.g., some Candida species in humans).
• _________– Fungi that live on or inside a host and cause harm (e.g., dermatophytes that cause ringworm).
chlorophyll
Saprophytes (Saprobes)
Symbionts
Commensals
Parasites
IMPORTANCE OF FUNGI
- Breaking down and recycling organic matter
- Food production (beer, cheese, bread)
- Antibiotics (penicillin)
- Drug (immunosuppressive drug, i.e. cyclosporine or CsA)
- Model system in molecular biology
Impact: PFH
Phytopathogen
Food spoilage
Human diseases
Phytopathogens (Plant Pathogens)
Some fungi cause devastating diseases in plants, leading to agricultural losses. Examples include:
• ________– Causes Panama disease in bananas.
• ________– Causes corn smut (tumor-like growths on corn).
• _________– Causes potato blight, responsible for the Irish Potato Famine.
Fusarium oxysporum f. sp. cubense (Foc)
Ustilago maydis
Phytophthora infestans
Food Spoilage
Certain fungi contaminate food, causing deterioration and the production of harmful toxins (mycotoxins). Common spoilage fungi include:
• _______– Some species produce aflatoxins, which are toxic and carcinogenic.
• _______– Can cause spoilage in fruits, bread, and dairy products.
• _______– Often found on rotting fruits and bread.
• _______– Can spoil beverages by fermenting unwanted sugars.
• _______– Can contaminate dairy and fruit juices.
Aspergillus
Penicillium
Rhizopus
Saccharomyces
Candida
Medical Importance
____types (___species)
About____ spp. cause human disease
___spp most pathogenic
~400,000
50,000
200
25
T or F: There are no nonpathogenic fungi!
TRUE
Kingdom
Nutritional type
Multicellularity
Cellular arrangement
Food acquisition method
Characteristic features
Embryo formation
- Fungi
- Chemoheterotroph
- All, except yeasts
- Unicellular, filamen-tous, fleshy (such
as mushrooms) - Absorptive
- Sexual and asexual spores
- None
FUNGI
Structural Characteristics
• ______organisms with a rigid cell wall composed of:
• _____(2) (providing structural integrity).
• Cell membrane contains_____ (instead of cholesterol, which is found in human cells).
• Can exist as: (3)
Eukaryotic
Chitin and glucan
ergosterol
• Unicellular (yeasts)
• Multicellular (molds)
• Dimorphic fungi (can switch between yeast and mold forms depending on temperature and environment).
FUNGI
Metabolic and Growth Characteristics
• Oxygen Requirements:
• Most fungi are _____ (2)
• ________:
• Obtain nutrients by absorbing organic matter rather than photosynthesis.
• Secrete enzymes that break down a variety of organic materials into soluble nutrients, allowing them to thrive in diverse environments.
facultative anaerobes (can survive with or without oxygen) or strict aerobes (require oxygen).
Chemotrophic
FUNGI
Reproduction
• Reproduce sexually and/or asexually through:
• ________(in yeasts).
• ________(in molds and dimorphic fungi).
Budding or fission
Spore formation
FUNGI
Special Adaptations
• ________ – Cannot produce their own food via photosynthesis.
• pH and Environment:
• Prefer___ environments (pH____).
• Thrive in high___ concentrations.
• Amino Acid Metabolism:
• Synthesize lysine via the_____ (a unique fungal feature).
Non-photosynthetic (achlorophyllous)
acidic; 5-6
sugar
α-aminoadipic acid (α-aminoadipate) pathway
: Mushroom
: Study of fungi
: diseases caused by fungi
Mykos (Gk)
Mycology
Mycoses
: ability to grow as yeast at 37° C and as mold at room temp.
Dimorphism
: non-pigmented fungi
: pigment-producing fungi
Hyaline fungi
Dematiaceous fungi
: sausage-like elongation from daughter cells
Pseudohyphae
: threadlike tubular structures that elongate at their tips by apical extension (coenocytic, septate)
Hyphae
: matlike structures of hyphae (filamentous, hairy or wooly molds)
Mycelium
: growing on or beneath the surface of the agar
: hyphae that project above the surface of the medium
Vegetative hyphae
Aerial hyphae
: asexual reproductive elements (spores)
Conidia
Morphologic Classification of FUNGI
YEAST
MOLD
DIMORPHIC
YEASTS
General Characteristics
• Unicellular fungi that reproduce either by _____ or ____
budding or fission.
YEASTS
Microscopic Features
• Shape:______
• Reproduction:
•____– Small outgrowth (bud) forms on the parent cell.
•____– The bud that eventually detaches and becomes a new yeast cell.
•____– Chains of elongated yeast cells that resemble true hyphae but lack septa.
Oval to round
Budding
Blastospore
Pseudohyphae
YEASTS MICROSCOPIC CHARACTERISTICS
Oval to round
Budding
Blastospore
Pseudohyphae
YEASTS
Macroscopic Features (Colony Morphology)
• Yeast colonies are…
round
pasty or mucoid
opaque
cream-colored
MONOMORPHIC Yeasts (Exist only in yeast form)
(3) CCG
• Candida albicans
• Cryptococcus neoformans
• Geotrichum candidum
MOLDS
General Characteristics
• Multicellular fungi composed of_____ (long, branching filaments).
• Hyphal width:_____
• Hyphae form a network called__
hyphae
2–10 µm
mycelia
MOLDS
Hyphae form a network called mycelia,* which can be:
• _____– Grows into the substrate for nutrient absorption.
• _____– Produces spores for reproduction and elongates by apical extension.
Vegetative (Thallus)
Reproductive (Aerial)
MOLDS
Macroscopic Features (Colony Morphology)
• Mold colonies can appear…
cottony
hairy
woolly
velvety
granular
filamentous
MONOMORPHIC Molds (Exist only in mold form)
(3) MET
• Microsporum spp.
• Epidermophyton floccosum
• Trichophyton spp.
MOLDS
PIGMENTATION: observed…
front and reverse pigment
MOLDS
(3) CLASSIFICATION OF HYPHAE
A. EXISTENCE OF SEPTA
B. PRESENCE OF PIGMENT
C. HYPHAL SHAPES
MOLDS
Hyphae
Based on the Presence of Septa
1. _______– Sparsely septated (few or no divisions).
2. _______– Clearly divided by septa (cross-walls).
Coenocytic Hyphae
Septate Hyphae
MOLDS
Hyphae
Based on Pigmentation
•____– Non-pigmented, transparent.
•____– Darkly pigmented, contain melanin.
Hyaline Hyphae
Dematiaceous Hyphae
MOLDS
In Medically Important Fungi,
3 Types Of Hyphae:
1.____ - sparsely septated
2.____ - dark and pigmented septate hyphae
3.____ - septate, non-pigmented hyphae
Coenocytic
Dematiaceous fungi
Hyaline molds
Hyphal Shape
Pectinate Body
Nodular Organ
Spiral Hyphae
Favic Chandelier (Antler Hyphae)
Racquet Hyphae
shape
Microsporum audouinii
Pectinate Body
Shape
Microsporum canis
Nodular organ
Shape
Trichophyton mentagrophytes
Spiral hyphae
Shape
Trichophyton schoenleinii
Favic chandelier
Antler hyphae
Shape
Epidermophyton floccosum
Racquet hyphae
; an invasive property of pathogenic fungi
Ability to switch between two different morphological forms based on temperature.
Thermal dimorphism
DIMORPHIC FUNGI
• ______: At 35–37°C (found inside the host; invasive form).
• ______: At 25–30°C (found in the environment; saprophytic form).
Yeast form
Mold form
DIMORPHIC FUNGI
Microscopic Features
•____: Oval, elongated, or cigar-shaped yeast cells.
•\_\_\_\_: Brown to black filamentous colonies with thin septate hyphae, conidia in clusters, or a daisy-wheel pattern.
Yeast form
Mold form
DIMORPHIC FUNGI (SHBCPT)
- Sporothrix schenckii
- Histoplasma capsulatum
- Blastomyces dermatitidis
- Coccidioides immitis
- Paracoccidioides brasiliensis
- Talaromyces (Penicillium) marneffei
Subcutaneous/Systemic Mycosis
• – Causes .. (Rose gardener’s disease).
Sporothrix schenckii
Systemic Mycoses (Cause deep infections in immunocompetent individuals)
4
• Histoplasma capsulatum
• Blastomyces dermatitidis
• Coccidioides immitis
• Paracoccidioides brasiliensis
Opportunistic Mycosis (Affects immunocompromised patients)
• – Affects HIV/AIDS patients in Southeast Asia.
Talaromyces (Penicillium) marneffei
• _____are unicellular, reproduce by budding or fission, and form pasty or mucoid colonies.
• _____are multicellular, have hyphae, and produce cottony or filamentous colonies.
• _____fungi can switch between yeast (in host) and mold (in environment) forms and cause systemic or opportunistic infections.
Yeasts
Molds
Dimorphic
