Fungi - Lecture #37

Question 1

Fungi nucleus

Answer 1

Eukaryotic

Question 2

Fungi cell wall

Answer 2

Chitin , β (1,3) and β (1,6) glucans, mannose modified proteins, and glycosylphosphatidylinositol (GPI)- anchored proteins. The cell membrane has ergosterol

Question 3

Fungal Morphology - Mould

Answer 3

• Multicellular
• hyphae (septate or aspetate)
• mycelia

Question 4

Septa described

Answer 4

Septa are perforated: mitochondria or nuclei can migrate along a hyphal strand.

Question 5

Aspetate Described

Answer 5

are referred to as coenocytic, in that a single plasma membrane surrounds many nuclei creating a multinucleate cell.

Question 6

Dikaryon

Answer 6

A fungal cell with two haploid nuclei

Question 7

Dimorphic fungi - animal habitat

Answer 7

• Parasitic
• 35C - 40 C
• endospore reproduction
• yeast phase

Question 8

Dimorphic Fungi - Natural habitat

Answer 8

• Saprobic
• Mycelial phase
• <30C
• sporulation reproduction

Question 9

Asexual reproduction of fungi

Answer 9

-budding can be equal or unequal
-can form from hyphae or specialized hyphal structures
-

Question 10

Sexual reproduction of fungi

Answer 10

-fuses haploid gametes to produce a transient diploid zygote, which then produces haploid spores.

Question 11

Fungal Pathogenesis

Answer 11

• primary mycoses – respiratory portal; inhaled spores
• cutaneous and superficial – contamination of skin surface
• subcutaneous - inoculated skin; trauma

Question 12

Fungal Pathogenesis -Virulence Factors I

Answer 12

thermal dimorphism, toxin production, capsules and adhesion factors, hydrolytic enzymes, inflammatory stimulants

Question 13

Antifungal defenses

Answer 13

-integrity of the barriers and respiratory cilia
-cell-mediated immunity, phagocytosis, and
inflammation ( most NB)

Question 14

Fungal diseases can be classified into four major types

Answer 14

• Hypersensitivity
• Myotocicoses
• Mycetismus
• Infections (Mycoses )

Question 15

Mycotoxicoses

Answer 15

poisoning of man/animal by feeds/products contaminated by toxin producing fungi that colonize crops such as grains, corn, peanuts; lethal to poultry and livestock

Question 16

Mycetismus

Answer 16

ingestion of pre-formed toxins

Question 17

Ascomycota

Answer 17

-Sexual reproduction in a sack called an ascus with the
production of ascopspores
-Candida Albicans ,Pneumocystis jirovecii

Question 18

Basidiomycota

Answer 18

Sexual reproduction in a sack called a basidium with the production of basidiospores

• common mushrooms
• Cryptococcus neoformans.

Question 19

Zygomycota

Answer 19

• sexual reproduction by gametes and asexual reproduction with the formation of zygospores
• Mucor spp., Rhizopus spp. and Absidia spp.

Question 20

Deuteromycota

Answer 20

(mitosporic fungi, fungi imperfecti) - no recognizable form of sexual reproduction. Includes most pathogenic fungi
-Penicillium spp., Trichophyton, candida spp., Aspergillus spp

Question 21

Superficial mycoses

Answer 21

Colonization of the outer layers of skin, the hair and nails, produces superficial mycoses, rarely invade deeper tissues.

Question 22

Pityriasis (Tinea) versicolor - Superficial mycoses

Answer 22

caused by the dimorphic Malassezia furfur, which infects skin and alters color

Question 23

Tinea Nigra -superficial myoces

Answer 23

• Causes skin to darken

- caused by Hortaea werneckii

Question 24

Black piedra

Answer 24

superficial infection of the hair shaft caused by Piedra hortae. Also, white piedra.

Question 25

Onychomycosis-Superfical mycoses

Answer 25

fungal infection of fingernails and toenails caused by Trichophyton rubrum and T. mentagrophytes

Question 26

Cutaneous mycoses

Answer 26

- These macular, papular or pustular (herpetiform) lesions that itch and are spread by scratching. Infection is confined to cutaneous tissue and rarely spread systemically. - causative agents - soil organisms introduced to extremities by trauma

Question 27

Cuntaneous Mycoses illnesses

Answer 27

- Tinea barbae - Tinea pedis - Tinea cruris - Tinea corporis - Tinea capitis

Question 28

Subcutaneous Mycoses

Answer 28

-Involve skin and deep viscera

Question 29

Sporotrichosis-Subcutaneous Mycoses

Answer 29

a subacute or chronic granulomatous infection, often following lymphatics, caused by the soil fungus Sporothrix schenckii

Question 30

mycetoma

Answer 30

is a granulomatous inflammation that may extend beneath the subcutaneous region to bone. Pigmented nodules may drain through sinuses and produce colored grains

Question 31

Chromoblastomycosis

Answer 31

an infection that forms | warty pigmented lesions which grow outward from

Question 32

Candidiasis

Answer 32

- opportunistic mycotic infection - off white ,pasty colony - causative agent of thrush , yeast infections and cutaneous candidas

Question 33

Aspergillosis

Answer 33

Verycommonairbornesoilfungus,usuallyinfectinglungs • Serious opportunistic threat to AIDS, leukemia, and transplant patients • Invasive aspergillosis can involve many organs

Question 34

Cryptococcosis - opportunistic infection

Answer 34

- inhabits soil around pigeon roots - affects lungs and brain - common infection of AIDS ,cancer or diabetes patients

Question 35

Zygomycosis/mucormycosis

Answer 35

- opportunistic infection | - Sabrobic fungi in soil ,water ,organic debris and food

Question 36

Pneumocystis

Answer 36

- pneumocystis jiroveci causes PCP - most prominent infection in those with AIDS - can be fatal without medication

Question 37

Fungal culture medium

Answer 37

-SDA (ph -5.4) - potato dextrasagar, Brain heart infusion Czapek dox agar - can be used isolation and to help for identification

Question 38

What does yeast look like microscopically

Answer 38

= oval = budding - encapsulated

Question 39

Molds microscopically

Answer 39

- Hyphae | - spores

Question 40

Fungal Stains

Answer 40

- 10 % KOH | - A calcoflour white / gram stain (stains positive) -Gomori - methenamine silver staining

Question 41

Low angle branching of hyphae

Answer 41

Aspergillus spp

Question 42

Right angle branching of hyphae and aspetate

Answer 42

Zygomycetes

Question 43

Sporangia

Answer 43

Enclosed spores

Question 44

Conidiophores

Answer 44

Open spores

Question 45

Phialides

Answer 45

Flask shaped cells from which conidia bud

Question 46

Arthospores

Answer 46

Cells that become conadia as they break off from the end of hypha

Question 47

Blastospores

Answer 47

-produced by budding at the ends of phialides.

Question 48

Chlamydospores

Answer 48

Thick walled spores capable of surviving adverse conditions

Question 49

Conidial structure

Answer 49

Macro or micro conidia | Tuberculate (knobbly appearance of a spore )

Question 50

Control of fungal infection

Answer 50

➢inhibition of ergosterol, beta-glucan and chitin biosynthetic pathways, ➢ inhibition of DNA synthesis by depleting thymine pools