Mimm 465 - Bacterial Pathogenesis (L2)

Front 1

Why are the GI, urogenital tract and lungs great environments for bacteria? (Three reasons)

Back 1

1. Warm
2. Humid
3. pH between 7 and 7.4

Front 2

How can bacteria invade innate immunity? (Three reasons)

Back 2

1. Attach and penetrate body surfaces.
2. Introduced by biting insect
3. Take advantage of preliminary damage (wound)

Front 3

What is the role/function of the following characteristics of skin defenses :
1. dry and acidic
2. dead, keratinized cells
3. sloughing of surface cells
4. toxic lipids/lysozymes
5. normal microbiota
6. Langerhans cells

Back 3

1. Prevents bacterial growth
2. Prevent colonization, keratin hard to degrade
3. Remove adherent bacteria
4. Protect hair follicles, sweat and sebaceous glands
5. Compete with pathogenic bacteria
6. Fight off bacteria at dermis level

Front 4

True or false : Normal microbiota usually Gram-positive.

Back 4

False. Gram-negative.

Front 5

Are simple epithelial cells more vulnerable to infection than stratified epithelial cells? Where can the latter be found? And the former?

Back 5

Yes. Simple epithelial cells are found in the intestinal tract. Stratified epithelial cells are present in the skin, the mouth.

Front 6

What are the barriers to bacterial invasion at the following sites :
1. Eyes (2)
2. Nasopharynx (2)
3. Nose (1)
4. Lungs (5)

Back 6

1. Blinking and tears (lysozymes, IgA, lactoferrin)
2. Resident microflora (G+ cocci), secretions.
3. Hair
4. Curved path cerates turbulence, coughing, sneezing, ciliated cells, macrophages

Front 7

What are the barriers to bacterial invasion at the following sites in the intestinal tract:
1. Mouth (6)
2. Stomach (2)
3. Small intestine (3)
4. Large intestine (4)

Back 7

1. Sloughing cells, saliva, lysozymes, IgA, resident microflora, lactoferrin.
2. pH is low, proteolytic enzymes
3. Fast flow, mucus, sloughing cells
4. Slow flow, mucus, sloughing cells, abundant resident microflora

Front 8

What is the function of the M cells?

Back 8

Take up antigen and transfer them to the basement membrane, where they are taken up by APCs.

Front 9

What are the barriers to bacterial invasion at the following sites in the urogenital tract:
1. Bladder (3)
2. Vagina/Cervix (2)

Back 9

1. Flushing action of urine, low pH, physical barrier of urethra
2. Resident microflora, low pH

Front 10

What is the function of the mucus plug? Where is it located?

Back 10

Located at cervical opening. Protects uterus and fallopian tubes.

Front 11

Urinary tract infections are ____ more common in females than males.

Back 11

20 times

Front 12

Mucus is produced by _____. It is viscous, slimy and acts as a lubricant. Its role is to ____ bacteria and prevent ____ to epithelial cells. Excess mucus is eliminated via ____ and ____.

Back 12

goblet cells, trap, attachment, fluid flow and cilia

Front 13

What nonspecific compounds do the mucus/saliva/tears contain to fight off bacterial infections?

Back 13

Lysozymes, lactoferrin.

Front 14

What is the function of lactoferrin?

Back 14

Sequester iron, which is essential for bacteria. The n-terminus of bacteria may bind LPS and further protect the host.

Front 15

Explain how defensins are activated in the crypt of the intestine and how they act on bacteria.

Back 15

In the presence of bacteria, zymogen is activated and converted into trypsin, which clips prodefensins to produce the active defensin (HD-5), which punches holes in bacteria. HD-5s bind strongly to bacterial cytoplasmic membranes, as they are amphipathic and the bacteria's CMs are negatively charged.

Front 16

True or false :
1. Bacteria can be found on the vagina, the cervix, the uterus and the upper genital tract.

Back 16

False. Only in vagina/cervix.
The uterus and upper genital tract are sterile. These sites are more vulnerable to bacteria, as they have no normal colonization.

Front 17

Which bacterial species can survive in the lymph nodes?

Back 17

Yersinia pestis.

Front 18

List the key features of the phagosome and describe them (4).

Back 18

Production of O2- : patients with defective NADPHox fail to kill many strains of bact/yeasts/fungi.
Proteolytic activity : mice lacking elastase and cathepsin G are compromised in terms of fighting off infections
low pH and ionic strength

Front 19

What produces NO? What reaction leads to NO production? What can NO do? What leads to the production of peroxynitrate? Which enzymes catalyzes the formation of peroxynitrate?

Back 19

Monocytes and macrophages.
L-Arginine --> L-citrulline + NO.
NO can attack DNA and proteins.
Superoxide + NO --> peroxynitrate.
NOS (iNOS or cNOS)

Front 20

iNOS is expressed in which types of cells (name 5).

Back 20

Macrophages, microglia, neutrophils, eosinophils, fibroblasts, endothelial cells, epithelial cells, astroglia.

Front 21

Is iNOs a homodimer or a heterodimer? What does it require for dimerization? What cytokines upregulate its production? What cytokines downregulate its production?

Back 21

Homodimer. Requires calmodulin and heme group. IL-1, TNF, IFN-g. IL-10, TGF-beta, IL-4.

Front 22

What boosts the production of cNOS?

Back 22

Increase in calcium ions.

Front 23

iNOS is essential for the control of two species. Which ones?
It is detrimental to host against two species. Which ones?

Back 23

1. Salmonella typhimurium. Mycobacterium tuberculosis.
2. M. avium and S. pneumoniae

Front 24

How can lysosomes be detrimental to host?

Back 24

When released in the tissues, they may cause cell death.

Front 25

Cytotoxic cells release ____ and _____, which can induce apoptosis.

Back 25

perforins, granzymes.