Yest and mold Flashcards
(46 cards)
1
Q
Mycology
A
Macroscopic and microscopic organisms
Microbiology includes ONLY microscopic fungi
2
Q
Chemoheterotrophs
A
Use organic chemical substances as sources of energy
3
Q
Saprophytes
A
Obtaining nutrients from dead organic material
4
Q
Oxygen requirements
A
- Most fungi are obligate aerobes need oxygen
- Some yeasts, however, are facultatively anaerobic obtain through fermentation
5
Q
Chemical requirements for fungi
A
- Grow better in at pH 5
- Sabouraud Media is the selective media
- Acid inhibit growth
- Grow in high sugar and salt concentration; resistant to osmotic pressure
- Can grow in low moisture content
- Can metabolize complex carbohydrates
6
Q
Yeasts
A
- Monocellular. Occasionally
organised into pseudohyphae - Asexual reproduction
- Form white, smooth, round, uniform colonies
7
Q
Molds
A
- Pluricellular, organised into
hyphae - Asexual or sexual reproduction
- Fuzzy colonies with a variety of colours
8
Q
Similarities and differences between bacteria and fungi
A
- Fungi is eukaryotic whereas bacteria is prokayotic
- Sterol is present in fungi but not in bacteria
- Bacteria has Peptidoglycan whereas fungi has chitin
- Bigger nucleus and organelles in fungi but not bacteria
9
Q
Fungal vs mammalian cells
A
- Fungal has cell wall
- Plasma membrane possesses different sterols (ergosterol)
- Presence of vacuoles in fungi - Large compartments for storage of molecules, protein degradation
10
Q
Chitin
A
- layer, a long-chain polymer of
N-acetylglucosamine
11
Q
Glucans
A
- Polysaccharides of D-glucose monomers network
12
Q
Mannoproteins
A
- Glycoprotiens that are on the external side
13
Q
Echinocandin
A
- Targets the synthesis of glucans
14
Q
Polyenes
A
- Nystatin is an example of targets ergosterol and causes pores in the cell membrane
15
Q
Azoles
A
- Flucanzole is an example of allylamines prevent the synthesis of ergosterol
16
Q
Importance of fungi
A
- Degrading organic materials
- Making alcoholic beverages (wine, beer)
- Food preparation (bread, some cheeses, soy sauce)
- Commercial production of some organic acids (gallic, citric)
- Manufacturing of drugs (ciclosporins) and antibiotics (penicillin)
- Commensal microbes of normal microbiota
17
Q
Harmful effects of fungi
A
- Food spoilage
- Contamination of pharmaceutical preparations
- Causing diseases
- Example of mycoses
18
Q
Spread of mycoses
A
- Generally from the environment to people (by spores)
- By spores (moulds) or direct contacts (yeasts)
- Limited person-to-person spread
19
Q
Entry site of Mycoses
A
- Skin - direct contact, cuts, splinters
- Lungs - inhaling spores
20
Q
Virulence factors of mycoses
A
- Mycotoxins
- Enzymes
21
Q
Superfical fungal infection
A
- Outer skin layer or on hair shafts
caused mostly by yeasts example of black Piedra and dandruff
22
Q
Cutaneous fungal infections
A
- Affects keratin-containing tissues
- Example ringworms and atheletes foot
23
Q
Subcutaneous fungal infection
A
- Chronic infection of subdermal tissues may require surgical intervention
- Sporotrichosis is the example of infection
24
Q
Systemic fungal infection
A
- Infection deep within body, affects many tissues and organs such as Blastomycosis
25
Opportunistic fungal infection
- Caused by normal microbiota or fungi that are not usually pathogenic such as Candidiasis Aspergillosis
26
Pateients at risk of Mycoses
- Impaired immune system
- Surgery and long-term use of
corticosteroids
- Indwelling catheters
- Chemotherapy for malignant cancer, Solid organ
transplantation
27
Yeasts
- Unicellular and non-filamentous organisms with oval/spherical shape
28
Reproduction of yeast
- Asexual reproduction
- Most by budding
- New organism develops from an outgrowth (bud)
- ASYMETRICAL cell division at one particular site
- Parent remains the same
- Could be caused by binarry fission
29
Candida yeast
- Most clinically relevant yeast
30
Polymorphic yeast
- Pseudohyphae may be formed
- Budding yeast cells that remain attached to each other
31
Normal microbiota
- Lives in the oral cavity, GI and genital tracts
- common cause of fungal opportunistic infections
- Immunocompromised patients or when the microbiota is altered
32
Candidasis
- Infections caused by any species of Candida
- Oral lining of your mouth Candida
33
Genus Cryptococcus
- Spherical, single cell yeast
- Surrounded by a peculiar and unusual
polysaccharide capsule
34
Pathogen with low virulence
- Cryptococcus is NOT part of normal microbiota
* However, it causes serious infections merely in severely immune compromised
35
Moulds
- Multicellular organisms consisting of threadlike
tubular structures called hyphae
- The hyphae form together to produce a mat-like
structure called a mycelium
36
Vegetative mycelium
- Elongates to obtain nutrients and anchor the mould on the Agar
37
Aerial mycelium
- Grow on top and have
reproduction function and produces spores
38
Mould reproduction
- Sexual or asexual
* Mould can reproduce asexually by fragmentation:
- Fragment into sections and grow
39
Asexual spore production
- Organism produced by mitosis
40
Sexual spore production
- Involves the fusion of haploid spores (after meiosis)
from partner of opposite mating type
41
Genus Aspergillus
- Ubiquitous moulds found in soil, on plants
42
Pulmonary aspergillosis
- Interstitial pneumonitis or localized ball-shaped infiltrates
43
Invasive aspergillus
- Infection can
spread from lung to heart, brain, kidneys
44
Selective toxicity for antifungal drugs
- Challenging than antibiotics due to similarity with human cells
- toxicity is observed, especially in chronic infection
45
Treatment for aspergillosis
- Voriconazole Within the class of azoles targeting synthesis of ergosterol
46
Invasive candidiasis treatment
- Echinocandins targeting synthesis of glucans which is a component of the cell wall
