Fungi part A

Question 1

Fungi are single or multicell?
spores?
cholorphyll?

Answer 1

Eukaryotes
Spore-forming
No chlorophyll

Question 2

Fungi O2 use?

Answer 2

Most fungi are aerobic

some facultative and strict anaerobes

Question 3

fungi cell walls usually have?

Answer 3

Cell walls usually contain chitin

polysaccharide containing N-acetylglucosamine (NAG)

Question 4

possible fungi growth forms?

Answer 4

1. filamentous (molds)

2. unicellular (yeasts)

Question 5

filamentous growth

septate vs. coenocytic?

Answer 5

threadlike filaments =hyphae>mycelium = mass of hyphae
septate vs. coenocytic hyphae (with and without crosswalls between cells)
grow by extension of tip and branching

Question 6

unicellular growth

Answer 6

single cells (ovoid or spherical)
reproduce asexually by cell division (budding)
sexually by cell fusion and spore formation

Question 7

fungi possible reproductive means

Answer 7

sexual and asexual

Question 8

asexual reproduction

Answer 8

a. cell division= budding/ transverse division
Some yeast-form fungi perform asexual cell division by budding, other by transverse division (fission).

b. spore formation= spores released

Question 9

sexual reproduction, morphologies?

Answer 9

involves production of “sexual spores” by meiosis of a diploid cell

Anamorph: form producing asexual spores, often mold-like growth form

Teleomorph: form producing sexual spores, typically a fruiting body

Question 10

dimorphism of fungi

Answer 10

ability to grow as yeast form or mold form

many pathogenic fungi are dimorphic

Question 11

most likely fungal form in human body? exception?

Answer 11

yeast form more typical at human body temperature
Candida is exception to this
both forms of Candida exist inside and outside the body

Question 12

candida forms (hyphae/ growth?)

Answer 12

Candida actually forms pseudohyphae and pseudomycelia pseudohyphae -
hyphal growth is a modified budding where newly budded cells remain attached to mother cell

Question 13

non-dimorphic pathogenic fungi

Answer 13

Aspergillus - mold from only

Cryptococcus neoformans - yeast form only

Question 14

Mycoses -

Answer 14

fungal infections Classified by affected area of body
Superficial
Cutaneous
Subcutaneous
Systemic

Question 15

Primary mechanisms for fighting fungi:

Answer 15

Neutrophil phagocytosis and killing

T cell-mediated immunity

Question 16

Superficial mycoses
types
regions they occur

Answer 16

keratinized outer layers of skin, hair, and nails
Mild infections/minimal inflammatory response
Easy to treat or clears without treatment
Piedras and Tineas
mostly occur in tropics

Question 17

Piedras

common agents?

Answer 17

infections of hair shaft

Trichosporon beigelii and white piedra

Question 18

Tineas

Answer 18

infections involving outer layers of skin, nails, and hair
Malassezia furfur (skin) and Pityriasis versicolor

Question 19

most common superficial mycoses agents

Answer 19

Pityriasis versicolor and white peidra

Question 20

Pityriasis (tinea) versicolor
found where? 
sign? 
in the environment? 
transmission?

Answer 20

Disease found worldwide
Pigmented macules - not elevated but altered color
M. furfur not found in the environment
Human-to-human transmission

Question 21

Cutaneous mycoses

Answer 21

keratinized outer layers of skin, hair, and nails

Skin infections: no invasion beyond stratum corneum (outermost layer of epidermis)

BUT a more apparent host response is elicited (unlike superficial mycoses)

Question 22

genuses causing cutaneous mycoses

trophism/ effect on this tissue?

Answer 22

“Dermaphytes”
Microsporum
Trichophyton
Epidermophyton

Keratinophilic and keratinolytic

Question 23

Cutaneous mycoses cause what kind of fungal disease?

Answer 23

Cause tineas (”ringworm")
Tinea pedis = athlete's foot
Tinea cruris = jock itch
Characterized by inflammation-ring of inflammatory scaling

Question 24

Cutaneous mycoses transmission
soil?
animals?
Diagnosis?

Answer 24

Person-to person transmission
Some are soil organisms
Others are zoonoses
Diagnosis by microscopy of samples

Question 25

Subcutaneous mycoses
response to chemotherapy?
treatment?

Answer 25

dermis and subcutaneous tissue
Do not respond well to antifungal chemotherapy
Need to excise

Question 26

Sporotrichosis cause? spp?
from what source?
tx?

Answer 26

subcutaneous mycoses- Sporothrix schenkii

Thorns and splinters
Responds to oral potassium iodide

Question 27

Systemic mycoses
caused by?
saprobes?

Answer 27

invade internal organs
caused by endemic dimorphic fungal pathogens
saprobe - organism living on dead or decaying matter

Question 28

possible agents of systemic mycoses
forms?
diseases?

Answer 28

all can be mold/mycelial in environment form or yeast form in our body, except Coccidioides immitis, this forms spherules in body

Histoplasma capsulatum= Histoplasmosis

Blastomyces dermatitidis= Blastomycosis

Coccidioides immitis= Coccidioidomycosis

Question 29

Spherule

Answer 29

100s of endospores, characteristic of Coccidioides immitis

Question 30

Histoplasma capsulatum from where/ how acquired?

Answer 30

Bird or bat droppings (high nitrogen content)

Acquire fungus by inhalation of conidia (asexual spores)

Question 31

Histoplasma capsulatum in macrophages

Answer 31

Organism remains viable within macrophages

modulate pH of phagolysosome

Question 32

Histoplasma capsulatum immunity

Ab? CMI?

Answer 32

Antibody plays no role in resolution

Cell-mediated immune system of CD4 T lymphocytes and activated macrophages are important for immunity

Question 33

Histoplasma capsulatum symptoms intially? progression? reactivation?

Answer 33

Primary infections most often asymptomatic

Granulomas develop in lung with caseous necrosis (plus calcification)

reactivation infection can occur years later

Question 34

Histoplasma capsulatum treatment

Answer 34

3-12 months of antifungal agent

Question 35

Histoplasma capsulatum environment vs tissue forms

Answer 35

environment: mold
tissue: yeast

Question 36

Blastomyces dermatiditis
found where?
how acquired?

Answer 36

Found in decaying matter (e.g leave litter)

Acquire fungus by inhalation of conidia (asexual spore)

Question 37

Blastomyces dermatiditis immunity

Answer 37

Cell-mediated immune system of CD4 T
lymphocytes and activated macrophages
are important for immunity

Question 38

Blastomyces dermatiditis primary infection symptoms?
progression? reactivation?
hallmark of disease?

Answer 38

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

Question 39

Blastomyces dermatiditis diagnosis/ treatment length

Answer 39

histopathological examination (thick-walled yeasts with single broad-based bud)
antifungal agents for 6-12 months

Question 40

Coccidioides immitis found where

Answer 40

Southwestern USA = lower Sonoran life zone

Huge “blooms”

Question 41

Coccidioides immitis targets

Answer 41

Lung is primary target but the fungus spreads through

the circulatory system and infects many organs

Question 42

Coccidioides immitis symptoms
large amount innoculate?
common name of dx?
dissementation?

Answer 42

Usually no symptoms - cell-mediated immunity

Sometimes with large amount of innoculate: acute pulmonary infection, arthralgias and skin lesions

“desert rheumatism” or “valley fever”

Disseminated coccidioidomycosis= chronic meningitis -fatal if not treated (lifelong)

Question 43

Coccidioides immitis diagnosis/ treatment length

Answer 43

presence of spherules

treated over 12-24 months