Fungi

Question 1

Fungi are

Answer 1

Eukar and heterotrophic

Question 2

Nomenclature

Answer 2

Mycota- mycetes- ales-acea

Question 3

GENERAL CHARACTERISTICS

Answer 3

● Unlike animals, most fungi are nonmotile and
possess a rigid cell wall.
● Unlike plants, fungi are non photosynthetic
● Approximately 80,000 species of fungi but fewer
than 400 are medically important and less than
50 species of fungi cause more than 90% of
fungal infections of humans and other animals.
● Has at least one nucleus with nuclear membrane,
ER, mitochondria & secretory apparatus.
● Most are obligate or facultative aerobes
● They are chemotropic; secreting enzymes that
degrade organic substrates into soluble nutrients
passively taken into the cell by active transport.

Question 4

Fungal infections are

Answer 4

mycoses

Question 5

yeast

Answer 5

● Baking

● Brewing

Question 6

antibiotics

Answer 6

● Penicillin
● Cephalosporin
Cyclosporin

Question 7

foods

Answer 7

● Cheeses
● Blue
● Roquefort

Question 8

steroids

Answer 8

● Hormones (reproductive)

Question 9

experimental

Answer 9

● Metabolic studies

● Pathway studies

Question 10

BIOREMEDIATION

Answer 10

● The use of some microorganisms to correct
mistakes in the environment

● Furthermore, in comparison with eight other
genera, aspergillus and penicillium species were
the most efficient metaboliser of hydrocarbons.
● Cyanide in mining operations

Question 11

Oil spills:

Answer 11

Mucorales and Monilales, as well as in
the genera aspergillus and penicillin (order
eurotiales).

Question 12

BAD EFFECTS OF THE FUNGI

Answer 12

● Destruction/Damages
● Food spoilage
● Crop destruction (photo pathogens) e.g
strawberry roasts.
● Diseases - Harmful effects
● Destruction of wood and other part of the body

Question 13

HYPERSENSITIVITY

Answer 13

An allergic reaction to molds and spores

Question 14

Farmer’s lung-

Answer 14

moldy hay

Question 15

Malt worker’s disease-

Answer 15

moldy barley

Question 16

Cheese washer’s lung-

Answer 16

moldy cheese

Question 17

Wood trimmer’s disease-

Answer 17

moldy wood

Question 18

MYCOTOXICOSES

Answer 18

Poisoning of man and animals by food products
contaminated by fungi which produce toxins from
the grain substance
● Copra may also be devastated by the myecitus
group

Question 19

MYCETISMUS

Answer 19

● The ingestion of toxins (amanita mushroom
poisoning)
● Not all mushrooms (biggest fungus) are edible

Question 20

INFECTION

Answer 20

● Tissue invasion with a host response
● Diseases caused by fungi are referred to as the
mycoses

Question 21

Tinea Nigra (Superficial)

Answer 21

○ Tinea nigra (or tinea nigra palmaris) is a
superficial chronic and asymptomatic
infection of the stratum corneum caused
by the dematiaceous fungus Hortaea
(Exophiala) werneckii.
○ The lesions appear as a dark (brown to
black) discoloration, often on the palm.
○ Microscopic examination of skin
scrapings from the periphery of the lesion
will reveal branched, septate hyphae and
budding yeast cells with melanized cell
walls.

Question 22

Pityriasis versicolor (Superficial)

Answer 22

○ Pityriasis versicolor is a highly prevalent,
chronic superficial infection of the
stratum corneum caused by species of
the lipophilic yeast, Malassezia.
○ Mainly caused by the organism
Malassezia furfur; the reaction of the
melanocytes from the sun will be
protected producing a whitish color if the
person has brown skin; if the person has
white skin, the area will be darker than
the normal skin
○ The infection is characterized by
discrete, serpentine, hyper- or hypo
pigmented maculae that develop on the
skin, usually on the chest, upper back,
arms, or abdomen. These patches of
discolored skin may enlarge and
coalesce, but scaling, inflammation, and
irrita- tion are minimal.

Question 23

Black Piedra (Superficial)

Answer 23

a nodular infection of the hair shaft

caused by Piedraia hortae

Question 24

White Piedra (Superficial)

Answer 24

due to infection with Trichosporon
species, presents as larger, softer,
yellowish nodules on the hairs

Question 25

Athlete’s foot (Cut)

Answer 25

(TineaPedis

Question 26

Ringworm (Cuta)

Answer 26

Tinea corporis

Question 27

Dermatophytosis (Cuta)

Answer 27

Organism/s involved: Microsporum spp, Trichophyton spp & Epidermophyton floccosu

Question 28

Candidias (cuta)

Answer 28

○ Organism involved: Candida albicans & | other speci

Question 29

SPOROTRICHOS (SubQ)

Answer 29

○ Sporothrix schenckii is a thermally dimorphic fungus that lives on vegetation ○ S. schenckii are introduced into the skin by trauma and cause sporotrichosis, a chronic granulomatous infectio

Question 30

● Mycetomas (SubQ)

Answer 30

``` ○ chronic subcutaneous infection induced by traumatic inoculation with any of several saprophytic species of fungi or actinomycetous bacteria that are normally found in soil. ○ The clinical features defining mycetoma are local swelling of the infected tissue and interconnecting, often draining, sinuses or fistulae that contain granules, which are microcolonies of the agent embedded in tissue material. ○ An actinomycetoma is a mycetoma caused by an actinomycete; a eumycetoma (maduromycosis, Madura foot) is a mycetoma caused by a fung ```

Question 31

Chromoblastomycosis and | Phaeohyphomycosisv(SubQ)

Answer 31

``` similar diseases resulting from infection with dark-pigmented fungi. ○ Both are acquired by traumatic introduction of fungi into the skin. ○ Lesions may be extensive and can spread internally. ○ The two diseases are distinguished by differences in fungal morphology in tissue sections. ```

Question 32

Histoplasmosis (Systemic)

Answer 32

``` ○ Histoplasma capsulatum, which causes histoplasmosis, is associated primarily with bat and bird droppings in soil in the Ohio River valley. ○ Generally, histoplasmosis is an occupationally acquired disease, but recreational exposure does occur. H. capsulatum can be carried from the lungs inside macrophages ```

Question 33

Blastomycosis (Systemic)

Answer 33

``` ○ caused by Blastomyces dermatitidis, which normally lives in soil rich in organic material. ○ B. dermatitidis almost always spreads beyond the lungs to produce cutaneous lesions. ```

Question 34

Coccidioidomycosis (Systemic)

Answer 34

``` Coccidioides immitis, which is limited to deserts, causes coccidioidomycosis, which is common in AIDS patients. ○ Contaminated dust is a major source of transmission. ```

Question 35

Paracoccidioidomycosis (Systemic)

Answer 35

``` ○ Paracoccidioides brasiliensis causes paracoccidioidomycosis. ○ Following a pulmonary phase, the fungus spreads and creates permanently disfiguring lesions on the face and neck ```

Question 36

Oral candidiasis or thrush (opportunistic)

Answer 36

``` ○ Commonly seen on patients with acute immunodeficiency ○ Classified by: ○ Lungs = caused by true pathogenic fungi ○ Other organ systems = caused by saprophytes ```

Question 37

PATHOGENIC FUNGI

Answer 37

1. NORMAL HOST ● Systemic pathogens = 25 species ● Cutaneous pathogens = 33 species ● Subcutaneous pathogens = 10 species 2. IMMUNOCOMPROMISED HOST ● Opportunistic fungi = 300 species

Question 38

SEVERITY

Answer 38

● In general, the severity of mycotic infections depends more on the host immune system than on the virulence of the fungus. ● Fungi, in general, do not have very specific virulence factors,except for some.

Question 39

SPECIES

Answer 39

100,000 – 200,000 species ● About 300 are known to be pathogenic to man ● Earth is a moldy earth ● Most of them are soil saprophytes

Question 40

CHARACTERISTICS

Answer 40

``` ● Chemoheterotrophs (requires organic compounds for energy and a carbon source) ● Mainly terrestrial ● Lack Chlorophyll ○ Dark habitats ● Spore bearing ○ Reproduce sexually or asexually ● Thallus body ○ Collection or mass of the organism ○ Mass of hyphae ```

Question 41

Cell wall =

Answer 41

chitin, glucan

Question 42

Cell membrane

Answer 42

ergosterol

Question 43

Nucleus

Answer 43

○ Membrane bound | ○ Diploid chromosome

Question 44

Cytoplasm

Answer 44

○ Similar to plants ○ Differential ribosomal synthesis ○ Different microtubule protein

Question 45

Reproduction

Answer 45

○ Sexually (meiotic) | ○ Asexually (mitotic)

Question 46

Mode of nutrition

Answer 46

``` Heterotrophs ■ saprotrophs - dead organisms or their wastes (dung) ■ parasites - living cells of other fungi, plants or animals ```

Question 47

Molds

Answer 47

● Made of long filaments called hyphae ● Hyphal or mycelial colony or form of growth ● You see in culture “cotton-like” and “leathery-like”

Question 48

Yeast

Answer 48

Are non-filamentous unicellular fungi that are oval or spherical in shape ● Unicellular, spherical to ellipsoid (3-15um) fungal cells that usually reproduce by budding ● In some fungi, the two forms exist. Fungi, which remain as molds, are monomorphic molds while yeasts, which remain as yeasts are monomorphic yeasts. ● Most molds grow at room temperature (30 to 35). Generally, in the mold phase,if the organism enters the body, they will change into the yeast