Lecture 6

Question 1

2 types of virulence factors?

Answer 1

colonization of the host and damage to the host

Question 2

3 things that damage the host

Answer 2

ability to produce PAMPs, harmful exotoxins, and inducing autoimmune response

Question 3

what do pamps recognition promote?

Answer 3

synthesize and secrete inflammatory cytokines and chemokines

Question 4

what does the complement pathway lead to?

Answer 4

inflammation, opsonization of bacteria, chemotaxis of phagocytes

Question 5

what does the coagulation pathway lead to?

Answer 5

clotting of blood to stop bleeding, more inflammation, and localization of infection

Question 6

what do PAMPs activate?

Answer 6

toll like receptors (TLR’s)

Question 7

what are the three importances of nf-kb?

Answer 7

pro inflammatory response, anti-apoptopic function, cellular growth

Question 8

what is nf-kb before dimerization?

Answer 8

it is a transcription factor resting in the cytoplasm in complex with Ikb then its stimulated and released lkb and nfkb forms to go to nucleus and binds kb sites to activate target genes

Question 9

how do different heterodimers vary?

Answer 9

preference for kb binding sites, kinetics of nuclear translocation, and abundance in different cells

Question 10

what happens when TLR4 and LPS binding receptors together recognize LPS?

Answer 10

NF-kb is activated and induction of cytokines and other anti microbial genes

Question 11

what happens once nfkb releases cytokines?

Answer 11

activation of coagulation pathway, prostaglandins, leukotriens, and activation of complement pathways

Question 12

what specifically does the damage to the capillary walls?

Answer 12

chemokines cause neutrophils that are adhered to the capillary walls to release proteases and toxic oxygen radicals that harm

Question 13

what factors lead to acidosis?

Answer 13

combination of hypotension, hypovolemia, DIC, loss of perfusion and ARDS. all these lead to decreased cardiac output

Question 14

what factors lead to heart failure?

Answer 14

cytokine induced overproduction of Nitric Oxide by cardiac muscle

Question 15

prolonged vasodilation and increased capillary permeability do what?

Answer 15

plasma leaves the bloodstream and enter the tissue, decreased vascular resistance results in drop of BP and reduced perfusion of blood through tissues and organs, decreased volume of circulating blood

Question 16

activation of blood coagulation pathway and concurrent down regulation of anticoagulation does what?

Answer 16

clots form within the blood vessels throughout the body called disseminated intravascular coagulation, further drop in blood and oxygen supply through tissues and organs

Question 17

increased capillary permeability and injury to capillaries in the alveoli of the lungs does what

Answer 17

pulmonary edema and loss of gas exchange leads to acute respiratory distress syndrome

Question 18

what does reduced perfusion and capillary damage do?

Answer 18

impaired liver function and a failure to maintain normal blood glucose levels and kidney and bowel injury meningitis

Question 19

what are the percentages of responsibility for septicemia?

Answer 19

45% from gram positive, 45 from negative and 10 from fungi

Question 20

what are the direct enzymatic mechanisms that affect target cells from toxins?

Answer 20

facilitate spread through tissues, damage cell membranes, immunomodulatory, inhibit protein synthesis, inhibit release of neurotransmitters

Question 21

what does each subunit in subunit toxins do?

Answer 21

a subunit does enzymatic toxic activity, protein synthesis inhibitors, and adenylate cyclases
B unit mediates binding to host cell receptor, facilitates translocation of A sub unit

Question 22

what do proteolytic toxins do?

Answer 22

zinc metalloendoproteases inhibit release of neurotransmitters
IgA proteases- made from pathogens that colonize mucosal surface, can autosecrete, cleaves secretory IgA1

Question 23

what do pore forming toxins do?

Answer 23

rtx family is produced by many gram negative, induce cytolytic effects
sulfhydryl activated family is produced by gram positive, mediates escape from macrophage vacuole and activity is triggered by low pH

Question 24

what do cytoskeletal modulator toxins do?

Answer 24

alter host cell actin filament polymerization state, antiphagocytic and necrotic effects

Question 25

what do pyrogenic exotoxins do?

Answer 25

they are potent activators of T cells and T lymphocytes, suppress B cell responses, enhance susceptibility to LPS, and stimulate strong cytokine production

Question 26

what are some characteristics of SEB?

Answer 26

easily soluble in water, very resistant to temperature fluctuations

Question 27

what are the steps required for intoxication of cells by Dip toxin?

Answer 27

binding to the cell surface, activation by proteolytic cleavage by FURIN, receptor mediated endocytosis, conformational change within endosomes, translocation across the endosome membrane into cytosol, ADP-ribosylation of EF-2 (causes protein inhibition)

Question 28

when do autoimmune responses happen?

Answer 28

production of cross reacting antibodies, auto reactive cytotoxic t lymphocytes or CTLs which is further stimulated by the classical complement pathway what

Question 29

what are immune complexes and how do they cause problems?

Answer 29

formed when high levels of circulating antibodies react with certain bacterial antigens, they can lodge in filtering units such as the kidneys where they activate the complement pathway and destroy kidneys

Question 30

what are the gram negative type 1 secreted proteins?

Answer 30

RTX toxin, E. coli hemolysin, bacteriocins, metalloproteases

Question 31

what are the gram negative type 2 secreted proteins?

Answer 31

proteases, cellulases, pectinases, lipases, phospholipases, and AB toxins

Question 32

what bacteria use the type 4 gram negative secretion?

Answer 32

B pertussis- pertussis toxin, H pylori-CagA and L pneumophila

Question 33

what are the types of gram negative secretion systems? (just 1-3)

Answer 33

type 1- ATP binding cassette ABC transporter
type 2- general pathway (sec dependent) major secretory pathway
type 3- contact dependent translocation into eukaryotic cells

Question 34

types 4-5 and tat and srp secretion systems?

Answer 34

type 4- sec like dependent, translocation of DNA/protein complex
type 5- auto transporter (sec dependent) includes b-pore forming domain
Tat (twin arginine transport)- moves folded proteins across CM
SRP-(signal recognition particle)- sec dependent used for CM proteins

Question 35

what are the differences for gram positive secretion systems?

Answer 35

for type 3 it is instead oligolysin dependent translocation

there is no type 4