Fungi 1 Flashcards
Eukaryotes
Spore-forming
No chlorophyll
Fungi
What are the oxygen requirement of must fungi?
Aerobic
Cell walls of fungi usually contain ______ -polysaccharide containingN-acetyl-glucosamine (NAG)
chitin
\_\_\_\_\_\_ growth form of fungi: threadlike filaments =hyphae mycelium = mass of hyphae septate vs. coenocytichyphae (with and without crosswalls) grow by extension of tip and branching
Filamentous
______ growth form of fungi:
single cells (ovoid or spherical)
reproduce asexually by cell division (budding)
sexually by cell fusion and spore formation
- unicellular (yeasts
_____ reproduction includes cell division budding/ transverse division as well as spore formation
Asexual reproduction
_____ reproduction of fungi involves production of“sexual spores”by meiosis of a diploid cell
sexual reproduction
_______:form producing asexualspores,often mold-like growth form
Anamorph
________: form producing sexualspores,typically a fruiting body
Teleomorph
_______ -ability to grow as yeast form or mold form
dimorphism
many pathogenic fungi are _____
dimorphic
Which fungi is mentioned as being able to live in and outside of the body?
Candida
______ actually forms pseudohyphae and pseudomycelia
Candida
-hyphal growth is a modified budding where newly budded cells remain attached to mother cell
pseudohyphae
some pathogenic fungi are not dimorphic including what 2 fungi?
Aspergillus-mold from only
Cryptococcusneoformans-yeast form only
______-fungal infections
Classified by affected area of body
Mycoses
Primary mechanisms for fighting fungi is:
:Neutrophil phagocytosis and killing T cell-mediated immunity
keratinized outer layers of skin, hair, and nails
Mild infections/minimal inflammatory response
Easy to treat or clears without treatment
most occur in tropics
Include Piedras and Tineas
Superficial mycoses
: infections of hair shaft
-Trichosporon beigelii
Piedras
infections involving outer layers of skin, nails, and hair Malassezia furfur (skin)Pityriasis versicolor
Tineas
Disease found worldwide
Pigmented macules -not elevated but altered color
Human-to-human transmission
Pityriasis (tinea) versicolor
What is the agent of Pityriasis (tinea) versicolor?
(Malassezia furfur)
_______:
keratinized outer layers of skin, hair, and nailsSkin infections: no invasion beyond stratum corneum (outermost layer of epidermis)
BUT a more apparent host response is elicited (unlike superficial mycoses)
Person-to person transmission
Some are soil organisms
Others are zoonoses
Diagnosis by microscopy of samples
Cutaneous mycoses
The following are classified as \_\_\_\_\_\_\_: Microsporum Trichophyton Epidermophyton Keratinophilic and keratinolytic
“Dermaphytes”`
Cause tineas (”ringworm") Tinea pedis = athlete's foot Tinea cruris = jock itch Characterized by inflammation ring of inflammatory scaling
Cutaneous mycoses
_______
dermis and subcutaneous tissue
Do not respond well to antifungal chemotherapy
Need to excise
Subcutaneous mycoses
Sporothrix schenkii
Thorns and splinters
Responds to oral potassium iodide
(Subcutaneous mycoses)
Sporotrichosis
:invade internal organs caused by endemic dimorphic fungal pathogens
Systemic mycoses
-organism living on dead or decaying matter
saprobe
Histoplasma capsulatum is the agent of _________
Histoplasmosis
Blastomyces dermatitidis the agent of _________
Blastomycosisis
Coccidioides immitis is the agent of _________
Coccidioidomycosis
Bird or bat droppings (high nitrogen content)
Acquire fungus by inhalation of conidia
Histoplasma capsulatum
Organism remains viable within macrophages modulate pH of phagolysosome
Antibody plays no role in resolution
Cell-mediated immune system of CD4 T lymphocytes and activated macrophages are important for immunity
Primary infections most often asymptomatic
Granulomas develop in lung with caseous necrosis (plus calcification)
reactivation infection can occur years later
3-12 months of antifungal agent
Histoplasma capsulatum
Coccidioidomycosis: what is the yeast form of this?
Spherule
Found in decaying matter (e.g leave litter)
Acquire fungus by inhalation of conidia
Blastomyces dermatiditis
Cell-mediated immune system of CD4 T lymphocytes and activated macrophages are important for immunity
Primary infections symptomatic in <50% of patients
Granulomas develop with caseous necrosis (plus calcification)reactivation infection can occur years later
Cutaneous lesions are a hallmark of disease heaped up borders and small, central microabscesses
Diagnosis: histopathological examination (thick-walled yeasts with single broad-based bud)
Treatment; 6-12 months of antifungal agent
Blastomyces dermatiditis
Southwestern USA = lower Sonoran life zone
Huge “blooms”
Lung is primary target but the fungus spreads through the circulatory system and infects many organs
Usually no symptoms -cell-mediated immunity
Sometimes
acute pulmonary infection
arthralgias and skin lesions“desert rheumatism”or “valley fever”
Disseminated coccidioidomycosis
chronic meningitis -fatal if not treated (lifelong)
Diagnosis:histopathology -presence of spherules
Treatment- 12-24 months
Coccidioides immitis
