Microbio mycology

Question 1

general characteristics of fungi (7)

Answer 1

• eukaryotic- has membrane bound organelles
• non-photosynthetic
• heterotrophic
• cell wall contains glucan, mannan and chitin
• non motile
• cell membrane contains sterol (ergosterol)
• has 80s ribosomes

Question 2

hetertroph

Answer 2

must injest or absorb organic carbon in order to produce energy

Question 3

body structure of fungi

Answer 3

multicellular filaments= molds
single cells= yeasts
dimorphic= grow as both

Question 4

fungi reproduction

Answer 4

sexual (perfect) or asexual (imperfect)

produce spores

Question 5

mold- two types of mycelium

Answer 5

Vegetative- develops inside the substrate, provides support and absorbs nutrients
reproductive- differentiation to support the fruiting bodies, propagules. aerial

Question 6

mold- two types of hyphae

Answer 6

septate= cross walls that divide the hyphae into compartments
non septate= no compartments

Question 7

yeast- structure

Answer 7

non-filamentous unicellular that are spherical or oval

Question 8

yeast-reproduction

Answer 8

budding.

when buds fail to detach= pseudohyphae

Question 9

dimorphic fungi

Answer 9

change from mycelial from (at room temp) to yeast (at 37C or in issues of animals)

Question 10

what factors regulate dimorphism? (4)

Answer 10

temp, CO2 concentration, pH and levels of cysteine or other sulfhydryl contianing compunds

Question 11

Types of fungi that cause disease (4)

Answer 11

pathogentic- cause ringworm and mycoses
opportunistic- seldom cause disease
dimorphic and dermatophytes (pathogens)

Question 12

factors that may predispose to fungal invasion of tissues (7)

Answer 12

immunosuppression/immunological defects
prolonged antibody therapy
immaturity, aging, malutrition
exposure to heavy amounts of sores
traumatized tissue
persistane moisture on skin
neoplastic condition

Question 13

Classification of mysosis based on area of the body the infection (4)

Answer 13

1. superficial- outer skin layer. yeast, no immune response.
2. cutaneous (dermatophytoses)- epidermal layer. ringworm, athletes foot. immune response
3. subcutaneous- chronic infection of subdermal tissues. diphorphic fungi, mycetoma
4. deep/systemis- originating in the lung by dimorphic fungi. blastomycosis

Question 14

how is immunity to fungal infections mediated and what is a characteristic of most infections?

Answer 14

mainly cell-mediated. most lesions are granulomatous

Question 15

What are two examples of ringworm and what animals does it affect?

Answer 15

caused by microsporum or trichophyton. affects all domestic animals and man

Question 16

what is aspergilosis caused by and who does it effect?

Answer 16

aspergillus. affects cattle, horse, poultry

Question 17

who does candidiasis effect and what are the two main portal of entry for the pathogen?

Answer 17

candida albicans. affects avian, dogs, cats, man, pigs.
superficial or deep
main portals of entry= alimentary tract and IV catheters.

Question 18

what causes Blastomycosis and who does it effect?

Answer 18

clastomyces dermatidis. affects dogs, humans, cats, horses and maybe other animals. not zoonotic or contagious between dogs

Question 19

what is dermatophytes and what is it caused by? (3)

Answer 19

molds parasitize keratinized epidermal structures.
ring worm
zoonosis
caused by microsporum and trichophyton and epidermophyton

Question 20

opportunistic mycosis (cause and 3 examples)

Answer 20

caused by numerous fungi. most representative genera= mycosis.
candidia albicans, cryptococcus neoformans, aspergillus

Question 21

antifungal drug treatment description and example

Answer 21

drug that selectively eliminates fungal pathogens from a host with minimal toxicity to the host
amphotericin B binds with ergosterol

Question 22

antifunal drug mechanisms- polyene

Answer 22

amphotericin interact with sterols (ergosterol) in the cell membrane

Question 23

antifunal drug mechanisms- azole

Answer 23

fluconazole inhibit cytochrome P450- dependent enzymes involved in the biosynthesis of ergosterol

Question 24

antifungal drug mechanisms- allylamine and morpholine

Answer 24

terbinafine inhibit ergosterol biosynthesis

Question 25

antifungal drug mechanisms- antibetabolite

Answer 25

5-fluorocytosine acts as inhibitor for both DNA and RNA synthesis

Question 26

mycotoxins characteristics (2) and example

Answer 26

secondary chemicalmetabolite produced by fungi under stress. can contaminate feed. ex aflatoxin produced by aspergillus

Question 27

mycotoxicosis (3 examples)

Answer 27

rye mold produces ergot (alkaloid) and leads to ergotism
aspergillus produces alfatoxin can be carcinogenic
poisonous mushroom= amanita phalloides

Question 28

treatment and control

Answer 28

isolate infected animals
lime sulfur or miconazole shampoo
clip hair
systemic therapies
burn contaminated bedding and disinfect grooming equipment

Question 29

facultative parasite

Answer 29

organism may become parasitic but doesn’t require a host for completion of its life cycle

Question 30

opportunistic infection

Answer 30

cause by pathogens that take advantage of an opportunity not normally available

Question 31

Parasitism

Answer 31

when an organism derives its food from a living organism of another species by living in or on the body of the host. usually causes harm to some extent

Question 32

ectoparasite

Answer 32

living on the host. spend part of their life as free-living

Question 33

endoparasite

Answer 33

living inside the host

Question 34

micropora characteristics (5)

Answer 34

obligate intracellular protozoan parasite
infects every major animal group. mainly arthropods and fish
spore-forming
ultimate parasite.
opportunistic

Question 35

ultimate parasite characteristics (2)

Answer 35

reduced genome size, loss of essential biochemical pathway