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Microbiology > Genetics and toxins > Flashcards

Genetics and toxins Flashcards

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Biology 101 flashcards
1
Q

exotoxin coded where

A

plasmids and bacteriophages

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2
Q

endotoxin coded where

A

bacterial chromosome

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3
Q

antigenicity of exo and endo toxins

A

exotoxins very antigenic

endotoxins not antigenic

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4
Q

heat stability of exo and endo toxins

A

exotoxins: stable up to 60 degrees Celsius except for staph enterotoxin
endotoxin: stable for 1 hr in 100 degrees

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5
Q

examples of exotoxins

A

tetanus
botulism
diphtheria

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6
Q

examples of endotoxin

A

meningococcemia

GN sepsis

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7
Q

what are some things exotoxin can do (6)

A
  1. inhibit protein synthesis
  2. increase fluid secretion
  3. inhibit phagocytic activity
  4. inhibit release of NT
  5. lyse cell MB
  6. superantigens causing shock
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8
Q

what organisms’ exotoxins inhibit protein synthesis? (4)

A
  1. Corynebacterium diphtheriae
  2. Pseudomonas aeruginosa
  3. Shigella spp
  4. EHEC 0157:H7
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9
Q

Diphtheria toxin

  • who secretes it
  • action
  • clinical manifestation
A
  • corynebacterium diphtheriae.
  • inactivates elongation factor (EF2) to inhibit protein synthesis
  • pharyngitis w/pseudomembranes in th roat and severe LAD (bull neck)
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10
Q

exotoxin A

  • who secretes it
  • action
  • clinical manifestation
A
  • pseudomonas
  • inactivates elongation factor (EF2) to inhibit protein synthesis
  • host cell death
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11
Q

shiga toxin (ST)

  • who secretes it
  • action
  • clinical manifestation
A
  • Shigella spp
  • inactivates 60S subunit by removing adenine from rRNA
  • GI mucosal damage –> dysentry … potential HUS 2/2 cytokines
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12
Q

shiga-like toxin (SLT)

  • who secretes it
  • action
  • clinical manifestation
A
  • EHEC
  • inactivates 60S subunit by removing adenine from rRNA
  • enhances cytokine release –> HUS … cannot invade host cells
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13
Q

what organisms have exotoxins that can increase fluid secretion (3)

A
  1. ETEC
  2. vibrio cholera
  3. bacillus anthracis
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14
Q

heat-labile toxin (LT)

  • who secretes it
  • action
  • clinical manifestation
A
  • ETEC
  • increase cAMP –> increase Cl and H2O secretion in GI
  • watery diarrhea
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15
Q

heat-stable toxin (ST)

  • who secretes it
  • action
  • clinical manifestation
A
  • ETEC
  • increase cGMP –> decrease resorption of NaCl and water in gut
  • watery diarrhea
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16
Q

cholera toxin

  • who secretes it
  • action
  • clinical manifestation
A
  • vibrio cholerae
  • increases cAMP by permanent activation of Gs –> increase Cl and water excretion in GI
  • voluminous “rice-water” diarrhea
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17
Q

edema factor

  • who secretes it
  • action
  • clinical manifestation
A
  • bacillus anthracis
  • mimics AC –> increases cAMP
  • edmatous borders of black eschar in cutaneous anthrax
18
Q

what organism has exotoxin that inhibits phagocytic ability (1)

A
  1. bordetella pertussis
19
Q

pertussis toxin

  • who secretes it
  • action
  • clinical manifestation
A
  • bordetella pertussis
  • increase cAMP by disabiling Gi –> impairs phagocytosis
  • Whooping cough
20
Q

what organisms have exotoxins that inhibit release of NT (2)

A
  1. clostridium tetani

2. clostridium botulinum

21
Q

tetanospasmin

  • who secretes it
  • action
  • clinical manifestation
A
  • clostridium tetani
  • protease that cleaves SNAREs that release GABA
  • spasticity and lockjaw 2/2 inability relax
22
Q

botulinum toxin

  • who secretes it
  • action
  • clinical manifestation
A
  • clostridium botulinum
  • protease that cleaves SNAREs that release Ach
  • flaccid paralysis
23
Q

what organisms have exotoxins that lyse cell MBs? (2)

A
  1. clostridium perfringens

2. strep pyogenes

24
Q

alpha toxin

  • who secretes it
  • action
  • clinical manifestation
A
  • clostridium perfringens
  • phospholipase (lecithinase) that degrades tissue and cell MB
  • PL degradation –> myonecrosis (gas gangrene) and hemolysis (“double zone” of hemolysis on blood agar)
25
Q

streptolysin O

  • who secretes it
  • action
  • clinical manifestation
A
  • strep pyogenes
  • protein that degrades cell MB
  • lyses RBCs –> beta-hemolysis
    ASO titers used to dx rheumatic fever
26
Q

what organisms have exotoxins that cause shock (2)

A
  1. staph aureus

2. strep pyogenes

27
Q

toxic shock syndrome toxin (TSST-1)

  • who secretes it
  • action
  • clinical manifestation
A
  • staph aureus
  • recruits MHC-II and TCR to cause overwhelming release of IFN-gamma and IL-2 –> shock
  • fever, rash, shock
28
Q

exotoxin A

  • who secretes it
  • action
  • clinical manifestation
A
  • strep pyogenes
  • recruits MHC-II and TCR to cause overwhelming release of IGN-gamma and IL-2 –> shock
  • fever, rash, shock
29
Q

some consequences of endotoxin (9)

A

ENDOTOXIN

Edema
Nitric oxide
DIC / Death
On outer MB
TNF-alpha
O-antigen
Xtremely heat stable
IL-1
Neutrophil chemotaxis
30
Q

what three things does lipid A of endotoxin activate?

A
  1. activates macrophages
  2. activates copmlement
  3. activates TF
31
Q

consequences of LPS activating macrophages? (3)

A
  1. IL-1 –> fever
  2. TNF –> fever and hypotension
  3. NO –> hypotension
32
Q

consequences of LPS activating TF? (1)

A
  1. coagulation cascade –> DIC
33
Q

consequences of LPS activating complement? (2)

A
  1. C3a –> hypotension and edema

2. C5a –> neutrophil chemotaxis

34
Q

what is bacterial transformation?

A

taking up naked DNA from environment after cell lysis

35
Q

which organisms are better known for ability for transformation (3)

A

SHiN

strep pneumo
h flu
neisseira

36
Q

conjugation partners

A

F+ : has plasmid for genes of pilus and conjugation

F- the receiver

37
Q

what’s trasnferred in conjugation

A

just plasmid DNA, not actual bacterial chromosomal genes

38
Q

what’s transposition

A

where transposon (DNA segment) can jump from one location to another (b/w plasmid and genome etc)

39
Q

what are the two types of transductions?

A
  1. generalized

2. specialized

40
Q

what’s generalized transduction

A

“packaging event”
lytic phage infects bacterium, cleaves bacterial DNA and parts of bacterial DNA packaged in viral capsid

phage will then infect next cell and transfer genes

41
Q

what’s specialized transudction

A

“excision event”
lysogenic phage infects bacterium
viral DNA goes into bacterial DNA and excises out the flanking bacterial genes

42
Q

genes for which toxins are coded on lysogenic phages? (5)

A
  1. ShigA-like toxin
  2. Botulinum toxin
  3. Cholera toxin
  4. Diphtheria toxin
  5. Erythrogenic toxin of strep pyogenes

Microbiology (11 decks)

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