2017/2018 SAQ

Question 1

stages in the biofilm life cycle.

Answer 1

1. Attachment
2. Colonization
3. Growth
4. Maturation
5. Detachment

Question 2

Attachment

Biofilm

Answer 2

bacterial cells attaches to a surface

Question 3

Colonization

Biofilm

Answer 3

Bacteria multiplies
Extracellular matrix produced
Allows stick to surface and each other

Question 4

Growth

Biofilm

Answer 4

As more bacteria joins community
Biofilm grows in thickness and complexity

Question 5

Maturation

Biofilm

Answer 5

Biofilm is more stable
resistant to external factors

Question 6

Detachment

Answer 6

Bacteria/ Small clusters of cell detach from Biofilm
Disperse
Cycle restarts

Question 7

Method 1

16S rRNA sequencing

DNA-based methods

Classification of Bacteria

Answer 7

Identify bacteria
sequencing of conserved region of 16 rRNA gene
Varies between bacterial taxa

Question 8

Method 2

Whole-genome sequencing

DNA-based methods to classify bacteria

Answer 8

Sequence entire genome of bacterial strain
high-resolution phylogenetic analysis
Identify unique genetic marks

Question 9

Method 3

Multi-locus sequence typing

DNA- based methods to classify bacteria

Answer 9

MLST
Sequence several different genes across bacterial genome
More detailed analysis of genetic diversity
Allows strain level identification

Question 10

Key characteristics of cytopathogenic viruses in terms of their pathogenecity

Answer 10

visible damage to infected cells
lead to cell death
altered cell function
cell rounding
syncytium formation (fusion of multiple cells)
Inclusion body formation
Changes in cell morphology

Question 11

Cytopathic effects of cytopathogenic viruses

Answer 11

tissue damage
organ dysfunction
leads to clinical symptoms and disease

Question 12

One characterstic distinguish fungi from animals

Answer 12

fungi - hetertrophic
> absorb nutrients from environment
Animals
> ingest good and digest internally

Question 13

Characteristics distinguish fungi from plant kingdom

Answer 13

Fungi: No chorophyll> no photosynthesis; plants do to produce own food
Celll wall : chitin(fungi) cellulose (plants)
Fungi: Reproduce by spores > dispersed by wind
Plants: Reproduce by seeds. begetative propagation

Question 14

5main fungal phyla

mycota

Answer 14

1. Ascomycota
2. Basidiomycota
3. Zygomycota
4. Chytridiomycota
5. Glomeromycota

Question 15

Ascomycota

fungal phylum

Answer 15

largest fungal species
characterized by production of sexual spores in sac-like structures called asci.

Question 16

Basidiomycota

Fungal phylum

Answer 16

produces sexual spores on basidia structures
Important decomposers
mycorrhizal fungi

Question 17

Zygomycota

Fungal phylum

Answer 17

Produces tough, resistant zygospores as a result of sexual production
includes many soil dwelling and plant associted species

Question 18

Zygomycota

Fungal phylum

Answer 18

Produces tough, resistant zygospores as a result of sexual production
includes many soil dwelling and plant associted species

Question 19

Chytridiomycota

Answer 19

Motile zoospores
most primitive fungal group
many aquatic and soil dwelling species

Question 20

Glomeromycota

Fungal phylum

Answer 20

Fungi forms mutualistic associations with th eroot of plants
Known as arbuscular mycorrhizae

Question 21

Sexual reproduction: zygomycotina and ascomycontina

Answer 21

Zygo
- by producing thick walled zygospores as a result of fusion between 2 diff mating types
**
Asco
- produce sexual spores in asci (sac-like)

Question 22

Asexual reproduction: zygomycotina and ascomycontina

Answer 22

Zygo- by producing sporangia
Asco- producing conidia

Question 23

Habitat: zygomycotina and ascomycontina

Answer 23

zygo- Soil dwelling fungi
asco- wider range of habitat: oil, water, symbionts of plants or animals
> econimocally important: yeasts, molds and plant pathogens

Question 24

Uncomplicated UTIs

Answer 24

Healthy individuals w/ normal unirnary tracts
By single bacteria species
e.coli

Question 25

Infections: uncomplicated UTI

Answer 25

Bladder (cystitis)
Urethra (urethritis)
Painful urination
Frequent urination
Strong urge to urinate

Question 26

Complicated UTIs

Answer 26

people w/underlying UT abnormalities/comorbidities
>kidney stones,UT obstruction, dibaetes/immunosupression
Mutiple bacterial species

Question 27

Complicated UTIs infections

Answer 27

Kidney damage
systemic infection

Question 28

Complicated UTI treatment

Answer 28

Long course of antibiotic treatment
Surgical intervention to address the underlying condtion (some cases)

Question 29

List 4 protective characteristic of lactobacilli in vagina (chai)

Answer 29

1. Acidification
2. Hydrogen peroxide production
3. Competitive exclusion
4. Immunimodulation

Question 30

Lactobacilli: Acidification

Answer 30

Lactobacilli produce lactic acid
maintain acidic environment
ph 3.5-4.5
inhibit growth of pathogenic bacteria

Question 31

Lactobacilli: Hydrogen peroxide production

Answer 31

Some strains produce h2o2
has antimicrobial activity against wide range of bacteria and virus

Question 32

Lactobacilli:competitive exclusion

Answer 32

Lactobacilli compete w/pathogenic bacteria for adhesion sites on vaginal epithelium
Preventing colonization

Question 33

Lactobacilli:immunomodulation

Answer 33

Lactobacilli stimulate immune system
enhance production of antimicrobial peptides and cytokines
Protect against infection

Question 34

Species associated with intestinal health

Gut

Answer 34

Probiotic bacterium
Called Bifidobacterium

Question 35

Effector molecules produces Bifidobacterium

Answer 35

Short-chain fatty acids (SCFA) = butyrate
Modulates the balance of T-helper cells in the gut

Question 36

Function of butyrate

Answer 36

Promote differentiation and activity of regulatory T cells (Tregs)
Maintain immune tolerance
Prevent inflammation and autoimmunity
Inhibit pro-inflammatory T-helper 17 differentiation (Th17)
Promote anti-inflammatory T-helper 2 cells differentiation (Th2)
Overall effect: T- helper cel balance, promote intestinal health, prevent inflammatory bowel disease (IBD)

Question 37

Function of butyrate

Answer 37

Promote differentiation and activity of regulatory T cells (Tregs)
Maintain immune tolerance
Prevent inflammation and autoimmunity
Inhibit pro-inflammatory T-helper 17 differentiation (Th17)
Promote anti-inflammatory T-helper 2 cells differentiation (Th2)
Overall effect: T- helper cel balance, promote intestinal health, prevent inflammatory bowel disease (IBD)

Question 38

4 opportunistic pathogens associated with cystic fibrosis

`

Answer 38

1. Pseudomonas Aeruginosa
2. Burkholderia cepacia complex
3. Staphylococcus aureus
4. Aspergilluus fumigatus

Question 39

4 opportunistic pathogens associated with cystic fibrosis

`

Answer 39

1. Pseudomonas Aeruginosa
2. Burkholderia cepacia complex
3. Staphylococcus aureus
4. Aspergilluus fumigatus

Question 40

Name 5 viral infection which may lead to viral encephalitis (inflammation and swelling of the brain tissue)

Answer 40

1. HSV = Herpes Simplex Virus
2. VZV = Varicella-zoster virus
3. WNV = West Nile virus
4. JEV = Japanese encephalitis virus
5. TBEV = Tick-borne encephalitis virus

Question 41

2 virulence factprs essential to meningeal invasaion by Neisseria meningitis

Answer 41

1. Capsule
2. Type IV pili

Question 42

Role of capsule

​Meningeal invasIon by Neisseria meningitis

Answer 42

Thick polysaccharide layer that surroynds the bacteral cell
Protects it from phagocytosis by host immune cells
Essential for bacteria to survive in bloodstream and cross the blood-brain barrier to infect the meninges

Question 43

Role of IV Pili

​Meningeal invasIon by Neisseria meningitis

Answer 43

long, thin protein appendages extending from bacterial surface
Mediate adherence to host cells and tissues
Enable bacteri to bind to and invade thecells of the blood- brain barrire
Facilitate entry into the central nervous system